Guidance on Best Available Techniques and Best Environmental Practices for the Use Of

Guidance on best available techniques and best environmental practices for the use of perfluorooctane sulfonic acid (PFOS) and related chemicals listed under the Stockholm Convention on Persistent Organic Pollutants

Updated

January 2017

Disclaimer
The designations employed and the presentations in this publication are possible options, based on expert judgment, for the purpose of assisting countries in their actions to reduce or eliminate releases of perfluorooctane sulfonic acid (PFOS) and related chemicals listed in the Stockholm Convention. UNEP or contributory organizations cannot be liable for misuse of the information contained in this publication.

Contents

Abbreviations and Acronyms

1Introduction

1.1Purpose

1.2Structure and use of this document

1.3Perfluorooctane sulfonic acid (PFOS), its salts, and perfluorooctanesulfonyl fluoride (PFOSF)

1.3.1Chemicals listed in Part III of Annex B of the Convention

1.3.2Characteristics

1.3.3Risks

1.3.4Production and use

1.4Consideration of alternatives to PFOS, its salts and PFOS-related substances

1.4.1General considerations

1.4.2Chemical alternatives

1.5Summary of Best Available Techniques (BAT) and Best Environmental Practices (BEP) by process category

1.6Relationship to the Basel Convention

2General principles and guidance on BAT and BEP for managing PFOS and PFOS-related substances

2.1Best Environmental Practices (BEP)

2.1.1Environmental management systems

2.1.2Specific Education and training of employees

2.1.3Additional considerations for BAT and BEP

2.2General BAT and BEP measures applicable to handling all chemicals

2.3BEP Measures for Manufacturing of PFOS Containing or PFOS-Related Substances Containing Products

2.4General BEP Measures when Using PFOS and PFOS-Related Substances

2.5BEP Measures for Manufacturing of Alternatives to PFOS and PFOS-Related Substances

2.6General BEP measures when using Alternatives to PFOS and PFOS-related substances

3BAT and BEP measures for PFOS and PFOS-related substances for acceptable purpose applications

3.1Photo-imaging

3.1.1.Background

3.1.2.BAT and BEP for PFOS and PFOS-related substances

3.2Photoresist and Anti-Reflective Coatings for Semiconductors

3.2.1.Background

3.2.2.BAT and BEP for PFOS and PFOS-related substances

3.3Etching Agent for Compound Semiconductors and Ceramic Filters

3.3.1Background

3.3.2BAT and BEP for PFOS and PFOS-related substances

3.4Aviation hydraulic fluids

3.4.1Background

3.4.2BAT and BEP for PFOS and PFOS-related substances

3.5Metal Plating (hard metal plating) Only in Closed-Loop Systems

3.5.1Background

3.5.2BAT and BEP for PFOS and PFOS-related substances

3.6Certain medical devices

3.6.1Background

3.6.2BAT and BEP for PFOS and PFOS-related substances

3.7Firefighting foam

3.7.1Background

3.7.2Types of foams

3.7.3BAT and BEP for PFOS and PFOS-related substances

3.8Insect Baits for Control of Leaf-Cutting Ants from genus Atta spp. and Acromyrmex spp.

3.8.1Background

3.8.2BAT and BEP for PFOS and PFOS-related substances

4BAT and BEP measures for PFOS and PFOS-related substances for specific exemption applications

4.1Photo Masks in the Semiconductor and Liquid Crystal Display (LCD) Industries

4.1.1Background

4.1.2BAT and BEP for PFOS and PFOS-related substances

4.2Metal Plating (hard metal plating)

4.2.1Background

4.2.2BAT and BEP for PFOS and PFOS-related substances

4.3Metal Plating (decorative plating)

4.3.1Background

4.3.2BAT and BEP for PFOS and PFOS-related substances

4.4Electric and Electronic Parts for Some Colour Printers and Colour Copy Machines

4.4.1Background

4.4.2BAT and BEP for PFOS and PFOS-related substances

4.5Insecticides for Control of Red Imported Fire Ants and Termites

4.5.1Background

4.5.2BAT and BEP for PFOS and PFOS-related substances

4.6Chemically driven oil production

4.6.1Background

4.6.2BAT and BEP for PFOS and PFOS-related substances

4.7Expired Exemption - Carpets

4.7.1Background

4.7.2BAT and BEP for PFOS and PFOS-related substances

4.8Expired exemption - Leather and Apparel

4.8.1Background

4.8.2BAT and BEP for PFOS and PFOS-related substances

4.9Expired exemption - Textiles and Upholstery

4.9.1Background

4.9.2BAT and BEP for PFOS and PFOS-related substances

4.10Expired Exemption - Paper and packaging

4.10.1Background

4.10.2BAT and BEP for PFOS and PFOS-related substances

4.11Expired exemption - Coatings and coating additives

4.11.1Background

4.11.2BAT and BEP for PFOS and PFOS-related substances for Coatings

4.11.3BAT and BEP for PFOS and PFOS-related substances for Coatings Additives

4.12Expired exemptions - Rubber and plastics

4.12.1Background

4.12.2BAT and BEP for PFOS and PFOS-related substances

5References

Abbreviations and Acronyms

AFFF / aqueous film-forming foam
AR-AFF / alcohol resistant aqueous film-forming foam
ARC / anti-reflective coating
AR-FFFP / alcohol-resistant film-forming fluoroprotein
AR-FP / alcohol-resistant fluoroproteinfoam
BARC / bottom anti-reflective coating
BAT / best available techniques
BEP / best environmentalpractices
BREF / BAT Reference Document
CCD / charge-coupled device (technology for capturing digital images)
COP / Conference of Parties
DWR / durable water-repellent
ECF / electrochemical fluorination
EMS / environmental management system
ETFE / ethylene tetrafluoroethylene, a fluorine-based plastic
EtFOSA / N-Ethyl perfluorooctanesulfonamide
EtFOSE / N-Ethyl perfluorooctanesulfonamidoethanol
FFFP / film-forming fluoroproteinfoam
FOSA / N-Alkylperfluorooctanesulfonamide
FOSE / N-Alkylperfluorooctanesulfonamidoethanol
FP
GHS / Fluoroproteinfoam
Global Harmonization System
LCD / liquid crystal display
PASF
PBT / Perfluoroalkanesulfonylfluoride
persistent, bioaccumulative and toxic
PFAS / Per- and polyfluoroalkyl substances
PFBS / perfluorobutane sulfonic acid (F-(CF2)4-SO3H) /potassium perfluorobutane sulfonate (F-(CF2)4-SO3- K+)
PFOS / Perfluorooctanesulfonate
PFOSF / Perfluorooctanesulfonylfluoride
PFSA / Perfluoroalkane sulfonic acid
POPRC / Persistent Organic Pollutant Review Committee
POPs / persistent organic pollutants
SDS / safety data sheet
TARC / top anti-reflective coating
VOC / volatile organic compounds

1Introduction

1.1Purpose

The concept of best available techniques (BAT) is not aimed at the prescription of any specific technique or technology. BAT means the most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques for providing in principle the basis for release limitations designed to prevent and, where that is not practical, generally to reduce releases of chemicals and their impact on the environment as a whole. Best environmental practices (BEP)describe the application of the most appropriate combination of environmental control measures and strategies (Article 5, f (i) and (v) of the Stockholm Convention).

Article 3, paragraph 6 of the Stockholm Convention, requests Parties that have a specific exemption and/or acceptable purpose in accordance with Annex A or B to the Convention to take measures to ensure that any production or use under such exemption or purpose is carried out in a manner that prevents or minimizes human exposure and releases to the environment (i.e. applying BAT and BEP).

This guidance document has been developed to guide Parties in their actions to prevent or reduce releases of perfluorooctane sulfonic acid (PFOS), its salts and PFOS-related substances from production and use under the specific exemptions and acceptable purposes listed in the Convention at its 4th meeting in 2009 (COP-4, SC-4/17).This document includes most up-to-date information and knowledge and supersedes the previous version published as UNEP/POPS/COP.7/INF21.

1.2Structure and use of this document

Chapter 1 outlines the purpose and structure of this document. It also includes a brief overview of characteristics and uses of PFOS, its salts and PFOS-related substances, the relevant provisions under the Stockholm Convention and a summary of required measures under these provisions.Furthermore, Tables 3 and 4 summarize whether or not alternatives are available and in use for each “acceptable purpose” and “specific exemption”. Tables 5 and 6 provide a comprehensive summary of BAT and BEP for each “acceptable purpose” and “specific exemption”.

Chapter 2 includes high level BAT and BEP principles for general chemical management, general pesticide management and guidance for the management of PFOS and PFOS-related substances in particular.

Chapters 3and 4 provide specific guidance for the processes/applications listed as acceptable purposes andspecific exemptions under the Convention.Each section within these chapters provides a general description (Background) of the process/application in which PFOS, its salts and/or PFOS-related substances were/are used, including information on available alternatives for that use, and specific BAT and BEP guidance for management of PFOS and related substances and their alternatives in the respective process/application.

1.3Perfluorooctane sulfonic acid (PFOS), its salts, and perfluorooctanesulfonyl fluoride (PFOSF)

1.3.1Chemicals listed in Part III of Annex B of the Convention

Perfluorooctyl sulfonate (F-(CF2)8-SO3-) is a fully fluorinated (perfluorinated) anionic substance, which is commonly used as a salt or in the acid form (perfluorooctane sulfonic acid, PFOS). PFOS is not known to occur naturally and is synthesized from perfluorooctanesulfonylfluoride (PFOSF, F-(CF2)8-SO2F). PFOSF is a key intermediate to produce “PFOS-related substances”, i.e. all substances that contain one or more C8F17SO2-groups and that can, or is assumed, to degrade to PFOS in the environment (UNEP/POPS/COP.7/INF/26). For example, PFOSF is the key intermediate to produce PFOS, N-alkyl perfluorooctanesulphonamides (FOSAs,F-(CF2)8-SO2-NH(alkyl))or N-alkyl perfluorooctanesulfonamidoethanols(FOSEs,F-(CF2)8-SO2-N(alkyl)(CH2CH2OH)). FOSA derivativesare typically non-polymeric substances, such as EtFOSA which is used as a pesticide.FOSEs are key intermediates to produce other PFOS-related substances.For example, EtFOSE (N-ethyl perfluorooctanesulfonamidoethanol, F-(CF2)8-SO2-N(C2H5)(CH2CH2OH))is the key intermediate to produce PFOS-related fluorinated polymers such as poly(meth)acrylates and polyurethanes.See Figure 1 for an overview of the process scheme and how it relates to the major product categories.

All these substances belong to different subgroups in the large family of per- orpoly-fluoroalkyl substances (PFAS). PFOS belongs to the subgroup of perfluoroalkane sulfonic acids (PFSA) and PFOSF and its derivatives belong to the PASF (perfluoroalkanesulfonylfluoride) subgroup (Buck et al. 2011). In this document, PFOS, its salts and PFOSF and products made therefrom are often referred to as ‘’PFOS and PFOS-related substances’’.This term is restricted to compounds having the C8F17-SO2- or C8F17-SO3-group, i.e., fully fluorinated at the eight carbon atoms followed by a leaving group such as sulfonyl (-SO2) or sulfonate (-SO3). PFOS and PFOS-related substances as referred to in this document are characterized by the C8F17-moiety; they contain only C and F atoms in the PFOS-moiety and do not contain any hydrogen (H) or oxygen (O).

The structural formulae are shown in Table 1 below.

Table 1:Identity of PFOS and some key PFOS-related substances

Structural formula / Substance name and abbreviation / Formula
PFOS, its salts and PFOSF
/ Perfluorooctyl sulfonate
PFOS / F-(CF2)8-SO3-
C8F17-SO3-
/ Perfluorooctanesulfonylfluoride
PFOSF / F-(CF2)8-SO2F
C8F17-SO2F
PFOS-related substances (e.g., precursors)
/ Perfluorooctanesulfonamide
FOSA / F-(CF2)8-SO2-NH2
C8F17-SO2- NH2
/ N-methyl perfluorooctanesulfonamide
MeFOSA / F-(CF2)8-SO2-NH-CH3
C8F17-SO2-NHCH3
/ N-ethylperfluorooctanesulfonamide
EtFOSA
Also: sulfluramid / F-(CF2)8-SO2-NH-CH2CH3
C8F17-SO2- N(H)C2H5
/ N-methyl perfluorooctancesulfonamido ethanol
MeFOSE / F-(CF2)8-SO2-N(CH3)(CH2CH2OH
C8F17-SO2-N(CH3)(C2H4)-OH
/ N-ethyl perfluorooctanesulfonamido ethanol
EtFOSE / F-(CF2)8-SO2-N(C2H5)(CH2CH2OH
C8F17-SO2- N(C2H5)C2H4-OH
Not PFOS-related
/ Perfluorooctanoic acid
PFOA / F-(CF2)7-COOH
C7F15-COOH

1.3.2Characteristics

PFOS is persistent and has substantial bioaccumulation and biomagnifying properties, although it does not follow the classic pattern of other POPs by partitioning into fatty tissues; instead, it binds to proteins in blood and liver. It has the capacity to undergo long-range transport and has demonstrated ecotoxicity and toxicitytowards mammals (UNEP/POPS/POPRC.2/17/Add.5).

1.3.3Risks

At its second meeting, the POPs Review Committee has developed and adopted the risk profile for PFOS contained in document UNEP/POPS/POPRC.2/17/Add.5. The Committee concluded, in accordance with paragraph 7 (a) of Article 8 of the Convention, that PFOS is likely, as a result of its long-range environmental transport, to lead to significant adverse human health and environmental effects such that global action is warranted. At its third meeting, the Committee adopted the risk management evaluation for PFOS, which is set out in document UNEP/POPS/POPRC.3/20/Add.5. Detailed information on the risks posed by PFOSand PFOS-related substances can be found in the above-mentioned documents.

1.3.4Production and use

In 2009, PFOS, its salts and related substances were listed in Annex B to the Convention with specific exemptions and acceptable purposes for production and use in accordance with Part III of Annex B. Production and use shall be eliminated by all Parties except those that have notified the secretariat of the intention to produce and/or use them for the specific exemptions and acceptable purposes listed in Part I of Annex B.The list of uses for acceptable purposes or specific exemptions pursuant to Part I of Annex B is given in Table2 below. The register of specific exemptions and the register of acceptable purposes for PFOS and PFOS-related substanceshave been established and are maintained on the Convention’s website:

Table 2:Acceptable purposes and specific exemptions for production and use of PFOS and PFOS-related substances according toPart I of Annex B to the Stockholm Convention.

Acceptable purposes / Specific exemptions

1. Photo-imaging
2. Photoresist and anti-reflective coatings for semiconductors
3. Etching agent for compound semiconductors and ceramic filters
4. Aviation hydraulic fluids
5. Metal plating (hard metal plating) only in closed-loop systems
6. Certain medical devices (such as ethylene tetrafluoroethylene copolymer (ETFE) layers and radio opaque ETFE production, in-vitro diagnostic medical devices, and CCD colour filters)
7. Fire fighting foam
8. Insect baits for control of leaf-cutting ants from Atta spp. and Acromyrmex spp.

/

1. Photo masks in the semiconductor and liquid crystal display (LCD) industries
2. Metal plating (hard metal plating)
3. Metal plating (decorative plating)
4. Electric and electronic parts for some colour printers and colour copy machines
5. Insecticides for control of red imported fire ants and termites
6. Chemically driven oil production

Expired exemptions*

1. Carpets
2. Leather and apparel
3. Textiles and upholstery
4. Paper and packaging
5. Coatings and coating additives
6. Rubber and plastics

* Expired exemptions are highlighted in italic red colour throughout this document

Acceptable purposes have no limited time frame, unless specified otherwise by the Conference of the Parties.Specific exemptions expire five (5) years after the date of entry into force of the chemical under the Convention unless the party indicates an earlier date when registering for an exemption. The amendmentsto list PFOS, its salts and PFOSF entered into force for most of the parties on 26 August 2010.In 2015, by decision SC-7/1,the Conference of the Parties decided that “specific exemptions for the production and use of perfluorooctane sulfonic acid, its salts and perfluorooctane sulfonyl fluoride for carpets, leather and apparel, textiles and upholstery, paper and packaging, coatings and coating additives and rubber and plastics, no new registrations may be made with respect to them”.These expired specific exemptions are highlighted in red in the table above and throughout this document.

Over the last decade, many Parties have implemented national regulations addressing these substances.A goodoverview has recently been also published by the OECD/UNEP Global PFC Group (OECD 2015).

Figure 1 shows the process scheme to produce PFOSF and the major product categories and applications of PFOS and PFOS-related substances(with modifications from OECD 2002).

Figure 1:Process scheme and major product categories and applications of PFOSF, PFOS and PFOS-related substances, such as FOSA and FOSE and the non-polymeric and polymeric derivatives

Since most FOSE is incorporated into higher molecular weight polymers, it comprises only a portion of the mole fraction of the entire polymer in the final product. However, it should be noted that the secondary reactions used to produce non-polymeric or polymeric FOSE derivatives do not necessarily produce pure products. Typically, 1-2% of the final product is comprised of unreacted or partially reacted fluorinated starting materials or intermediates that are carried forward into the final product as impurities (3M 2000).This is an important aspect to consider in applying BAT and BEP in the case of industries using these materials and having emissions to the environment.Furthermore, these products may also contain PFOA as animpurity (Jiang et al. 2015). In 2015,PFOA has been proposed for listing and is under review by the POPs Review Committee (UNEP/POPS/POPRC.11/5).

1.4Consideration of alternatives to PFOS, its salts and PFOS-related substances

1.4.1General considerations

According to paragraph 4 of Part III of Annex B to the Convention, to reduce and ultimately eliminate the production and use of PFOS, its salts and PFOS-related chemicals,parties are encouraged to phase out uses when suitable alternative substances or methods are available. Guidance for consideration of alternatives has been developed by the POPsReview Committee(for the most recent document see UNEP/POPS/POPRC.12/INF/15).More detailed information on the availability and suitability of the alternatives are available in the source documents used for the development of the guidance.

The present document includes information on available alternatives for the uses listed as specific exemptions and acceptable purposes under the Convention, but sometimes refrains from assessing their technical suitability for specific processes due to incomplete information.Whenever possible, trade names and names of manufacturers of potential alternatives are provided assuming that market presence of such products indicate technical suitability as substitutes.A hazard-based assessment forsome of the alternatives has been conducted by the POPs Review Committee, based on an analysis as to whether or not the identified alternative substances meetthe numerical thresholds in Annex D of the Convention (UNEP/POPS/POPRC.10/INF/7/Rev.1).

Parties may use these reports as a source ofinformation when choosing alternatives to PFOS, its salts and PFOS-related substances. It should be noted that for alternatives which are listed in these reports:

• it is not always clear if these are drop-in replacements and/or whether process changes and/or product loadings would need to be modified.Suppliers of these chemicals may be able to provide additional information.
• their suitability to meet performance specification could not always be validated.
• parties need to ensure those are registered for their intended use in their jurisdiction.
• for those considered not likely to exhibit POP characteristics, hazardous characteristics (e.g. mutagenicity, carcinogenicity, reproductive and developmental toxicity, endocrine disruption, immune suppression or neurotoxicity) may still be exhibited. It is recommended to carefully review the Safety Data Sheet(SDS) in GHS format for each substance and to avoid using substances for which no, or an incomplete, SDS is provided by a supplier.
• it is unknown whether or not such alternatives are produced deploying best practices and to minimize unintended product content (such as unreacted raw material and other impurities).Suppliers of these chemicals may be able to provide additional information.

In summary, all potential alternatives and their suppliers should be carefully assessed by parties before being considered as suitable alternatives.